Fluorochemical compounds (sometimes called organofluorine compounds or fluorochemicals) are a class of substances which contain portions that are fluoroaliphatic or fluorocarbon in nature, e.g., nonpolar, hydrophobic, oleophobic, and chemically inert, and which may contain other portions that are functional in nature, e.g., polar and chemically reactive. The class includes some commercial substances which are familiar to the general public, such as those which give oil and water repellency and stain and soil resistance to textiles.
An industrial process for producing organofluorine compounds is the electrochemical fluorination process commercialized initially in the 1950s by Minnesota Mining and Manufacturing Company. This fluorination process, commonly referred to as the "Simons electrochemical fluorination process," is a highly energetic process which uses anhydrous hydrogen fluoride.
Another process for producing fluorochemical compounds is direct fluorination, but it is not significantly used today as an industrial process. In direct fluorination, the highly exothermic reaction of fluorine, F.sub.2, with organic compounds is accompanied by quick evolution of heat and possibly by one or more of such phenomena as carbon-carbon scission or fragmentation, polymer formation, ignition, combustion, and violent explosion, the heat removal being the main problem in direct fluorination--see, for example, U.S. Pat. No. 4,523,039 (Lagow et al.) and Kirk-Othmer "Encyclopedia of Chemical Technology", 3rd Ed., Vol. 10, pages 636, 840-855, John Wiley & Sons, Inc., New York (1980). Various diverse fluorination methods or techniques which have been proposed to overcome problems in direct fluorination are dilution of the fluorine with an inert gas, use of low temperatures, use of inert solvents to dissipate heat, use of partially-fluorinated starting materials, dilution of the organic feed, use of hydrogen fluoride scavengers, and combinations of these techniques.
A review article on direct fluorination is that of Lagow et al. in Progress in Inorganic Chemistry 26, 161-210 (1979). Recent advances in direct fluorination are described, for example, in U.S. Pat. No. 4,859,747 (Bierschenk et al.), U.S. Pat. No. 4,973,716 (Calini et al.), U.S. Pat. No. 5,076,949 (Kalota et al.), U.S. Pat. No. 5,093,432 (Bierschenk et al.) and U.S. Pat. No. 5,177,275 (Baucom et al.) and the international application WO 90/06296 (Costello et at.), published Jun. 14, 1990 under the Patent Cooperation Treaty. The Bierschenk et al. patent and Costello et al. publication describe direct fluorination carried out in the liquid phase in stirred tank reactors using solutions or dispersions of various hydrogen-containing compounds or organic substances in inert liquid media, such as certain chlorofluorocarbons ("CFCs"), e.g., Freon.TM. 113 1,1,2-trichlorotrifluoroethane (the use of which, while it readily dissolves a wide variety of organic substance, is being discontinued because of its atmospheric ozone depletion potential).